As you prepare to head off on vacation, you run through the list you have diligently prepared to make sure you haven’t forgotten anything. Clothes for all kinds of weather, something nice to wear when you find a good restaurant, toiletries, and so on. You check that the water is turned off, that you have left detailed notes for the petsitter, that your mobile phone is charged. And, these days, you check for compliance with security restrictions: that you haven’t accidentally put your eyedrops in your carryon bag, that all your liquids are in tiny bottles, that they are neatly packed in a quart-sized bag.

At the airport, things do not go quite as well as you expect. You’re standing in the security line, watching your shoes, your jacket, your sweater, your jewellery going through the x-ray scanner as men acting under the authority of the government scan you with detectors, examine your identification, look for telltale signs of nervousness. Perhaps they even profile you based on the clothing you wear, the shade of your skin, and your age, even though they never admit it.

One of them comes over to you as you move to retrieve your things from the plastic bins. He asks you, “Are these your items?” You’re uncertain why he’s asking but you acknowledge that they are. “Do you have anything in your bag that you’re not supposed to,” he asks. You say you don’t, but why is he asking? He holds up a vial containing white powder. “Did this come out of your bag?” You can feel your palms turn sweaty and a lump forms in your throat. Your voice cracks a bit when you say no, making you worry that it’s all going to make him more suspicious. His face is serious, accusing. “Are you sure?”

It is only after he has frightened you that he confesses it’s just a joke.

Too funny.

What I have described is not fantasy. In January of this year, an employee of the Transportation Security Administration engaged in this prank multiple times with passengers he knew were innocent. My objective in highlighting the story is not to blow it out of proportion — people do engage in pranks, some of which are inappropriate, and they properly acknowledge that their judgment was poor when they consider things more soberly. Instead, my objective is to remind us that the employees charged with implementing security at airports are human and the risk that they will act maliciously is not simply hypothetical.

This is of real concern as the government continues to deploy full-body scanners at airports as part of its security procedures. The scanners are technological marvels and it’s hard not to remember Arnold Schwarzenegger being scanned by something eerily similar in the movie Total Recall. Innocent people simply wanting to travel from one location to another — and without the government having any specific reason to suspect them of wrongdoing — are now expected to allow themselves to be scanned in a way that generates images of their naked bodies through their clothes. Reassurances that privacy protections are in place — by having the viewing officer remote from the scanner, by including imaging techniques that blur facial features, and by implementing a policy requiring deletion of the images — do not really strike at the heart of the privacy concerns. Even with these protections in place, extremely personal details of people’s bodies are displayed to government agents: colostomy appliances, penile implants, evidence of mastectomy or testectomy, and more.

Already it is known that many images have been saved, contrary to the policy. At least one federal security screener in Miami has already been arrested in a conflict that arose when a coworker mocked images of his naked body generated by one of the scanners. That story can be read here. A security worker at Heathrow airport was subject to discipline when he made lewd comments about a coworker who was accidentally imaged by a scanner. That story can be read here.

The deployment of full-body scanners has been challenged in litigation that raises a number of arguments in asserting that they are unlawful. First, the lawsuit alleges that the scanners violate the Fourth Amendment’s guarantee that people have the right “to be secure in their persons … against unreasonable searches and seizures.” It is well-settled that airport security by itself is not an “unreasonable” search that violates the Fourth Amendment. But there is a significant difference between having passengers walk through magnetometers to detect metal before subjecting them to a more thorough search and requiring that every passenger have their unclothed body imaged. To be constitutional, airport searches must be “minimally intrusive,” “well tailored to protect personal privacy,” and “neither more extensive nor more intensive than necessary under the circumstances to rule out the presence of weapons or explosives.” Do full-body scanners meet these criteria?

Perhaps most interesting about the lawsuit, though, is its allegation that the program violates the Religious Freedom Restoration Act. This act prohibits the government from burdening the exercise of a person’s religion, even from generally applicable rules. Many religions make physical modesty a part of their doctrine and rules that force all aircraft travelers to violate their beliefs regarding modesty may well violate the statute.

Airport security has a legitimate role and almost no one maintains that full-body scanners do not have a reasonable place in that security. What is objectionable is the uniform use of such a personally intrusive scanning technology on people who have raised no suspicion that they have any intention other than wanting to board a plane so they can travel from one place to another. Programs that make use of the scanners only when some suspicion exists — after detection of metal by a magnetometer, suspicious behavior, unusual ticket-purchasing patterns, and so on — would generate far less objection among travelers.

Benjamin Franklin has been quoted so frequently since the grim events of September 11, 2001 that to quote him again seems almost trite. But there is nevertheless truth in his warning, which rings especially cleanly in the way it reminds us that the issues we face today are really no different in kind from those faced by contemporaries of the framers of the Constitution: “Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety.” If our own bodies do not define an essential liberty … then what does?